Weak gravitational lensing (WL) is the phenomenon of image distortion by gravitational light deflection. Images of background sources are distorted by foreground matter structures. By measuring the distortion to percentage levels, the state-of-the-art studies have found WL as a powerful tool to constrain cosmology. The upcoming Stage-IV surveys such as LSST and Euclid are expected to provide high-quality constraints comparable to Planck.
In this talk, I will provide an overview on up-to-date WL studies and surveys. This will include scientific motivations, an introduction to theoretical basis, observational challenges, state-of-the-art results, and future perspectives. The talk will be accessible for non-cosmologists.